• Carbon letters
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• 제15권1호
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• pp.15-24
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• 2014

As a part of the electromagnetic spectrum, microwaves heat materials fast and efficiently via direct energy transfer, while conventional heating methods rely on conduction and convection. To date, the use of microwave heating in the research of carbon-based materials has been mainly limited to liquid solutions. However, more rapid and efficient heating is possible in electron-rich solid materials, because the target materials absorb the energy of microwaves effectively and exclusively. Carbon-based solid materials are suitable for microwave-heating due to the delocalized pi electrons from sp2-hybridized carbon networks. In this perspective review, research on the microwave heating of carbon-based solid materials is extensively investigated. This review includes basic theories of microwave heating, and applications in carbon nanotubes, graphite and other carbon-based materials. Finally, priority issues are discussed for the advanced use of microwave heating, which have been poorly understood so far: heating mechanism, temperature control, and penetration depth.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2009년도 학술발표대회
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• pp.213-214
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• 2009

In order to promote an efficiency CPB process, we developed microwave system in CPB process. The whiteness and penetration ability of microwave-CPB pre-treated fabrics were superior to CPB only. This results indicates that microwave-CPB pre-treatment promotes CPB efficiency in agent usages and batching time.

• 한국콘텐츠학회논문지
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• 제4권4호
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• pp.171-178
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• 2004

라디오 주파수 마이크로파는 시료에서 포도당 농도를 측정하기 위해 사용될 수 있다. 본 논문에서는 포도당을 포함하는 증류수, 샐라인, 인체 씨럼, 인체 혈액 용액에 대해서 상대 유전율을 측정함으로써 포도당 농도 측정의 예비 실험 결과를 보고한다. 근육과 같은 인체 조직의 포도당 농도 측정에서 마이크로파 방법은 NIR방법보다 투과 깊이가 약 100배 더 컸으며, 이것은 인체의 포도당을 비침습적인 검출에 더 유용한 장점이 된다. 실험에서 인체 혈액 용액에서 포도당 농도를 검출하기 위한 측정 감도는 5.8GHz부근에서 약 57mg/dl를 보였다.

• Carbon letters
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• 제24권
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• pp.62-72
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• 2017

The aim of this work was to evaluate the dielectric properties of impregnated and activated palm kernel shells (PKSs) samples using two activating agents, potassium carbonate ($K_2CO_3$) and sodium hydroxide (NaOH), at three impregnation ratios. The materials were characterized by moisture content, carbon content, ash content, thermal profile and functional groups. The dielectric properties were examined using an open-ended coaxial probe method at various microwave frequencies (1-6 GHz) and temperatures (25, 35, and $45^{\circ}C$). The results show that the dielectric properties varied with frequency, temperature, moisture content, carbon content and mass ratio of the ionic solids. PKSK1.75 (PKS impregnated with $K_2CO_3$ at a mass ratio of 1.75) and PKSN1.5 (PKS impregnated with NaOH at a mass ratio of 1.5) exhibited a high loss tangent ($tan{\delta}$) indicating the effectiveness of these materials to be heated by microwaves. $K_2CO_3$ and NaOH can act as a microwave absorber to enhance the efficiency of microwave heating for low loss PKSs. Materials with a high moisture content exhibit a high loss tangent but low penetration depth. The interplay of multiple operating frequencies is suggested to promote better microwave heating by considering the changes in the materials characteristics.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2006년도 High Temperature Superconductivity Vol.XVI
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• pp.28-28
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• 2006

• 한국식품과학회지
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• 제31권1호
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• pp.54-61
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• 1999

본 연구는 해동 중 발생하는 drip 손실, 미생물의 오염, 표면의 과열 등을 방지하면서 급속 해동 방법을 찾기 위해 동결 돈육에 여러 가지 해동 방법을 적용하였다. 4, 28, $50^{\circ}C$에서의 해동과 2,450, 915 MHz의 microwave를 이용하여 해동을 실시하였고, 915 MHz microwave 해동은 출력을 5, 10, 15 kW로 변화시키면서 단일 조사와 $120^{\circ}C$의 열풍을 함께 조사한 경우를 해동시간, 온도분포, drip 손실, 보수력, 표면색도, 총세균수를 측정하였다. 915 MHz microwave를 이용한 해동은 열전도에 의한 해동보다 2백배 이상 시간이 단축되었고, 2,450 MHz microwave를 이용한 해동 방법의 침투깊이의 제한에서 발생되는 문제를 개선시킬 수 있었으며 drip 손실, 보수력, 총세균수에 있어서 효과가 컸다. 저주파수(915 MHz), 저출력(5 kW)의 microwave와 대류 가열을 병용하여 품질 저하를 최소한으로 방지하면서 급속해동을 위한 산업적 이용이 가능한 것으로 기대할 수 있었다.

• 한국세라믹학회지
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• 제42권7호
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• pp.449-454
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• 2005

A waveguide method is developed to study the materials with relatively large dielectric constants at microwave range. Basically, the method is similar to the previous waveguide methods represented by short-circuit line and transmission/reflection measurement methods. However, the complex permittivity is not determined by the shift in resonance frequencies, but by numerical analysis of measured scattering parameters. In order to enhance microwave penetration into the specimen with relatively large permittivity, a dielectric plate with lower permittivity is employed for impedance matching. The influences of air gap between the specimen and waveguide wall are evaluated, and the corresponding errors are estimated. The propagation of higher order modes is also considered. Experimental results for several reference ceramics are presented.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.109-110
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• 2022

Currently, interest in the quality of concrete is increasing. Among the important factors for evaluating the quality of concrete, interest in unit-water content is also increasing. Currently, the air-meter method, the microwave oven drying method, the capacitance method, and the microwave penetration method are used to measure the unit-water content of concrete.. Among the above methods, except for the microwave method, the measurement method is complicated, portability is reduced, and economic efficiency is reduced. This research aims to measure a unit-water content by using a Frequency Domain Reflectometry(FDR) sensor that is economical, simple to measure, and portable among microwave methods. In addition, it is an experimental study to determine the accuracy of unit-water content using a single input residual model during deep learning to solve the limitations of the FDR sensor.

• 한국식품조리과학회지
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• 제14권1호
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• pp.44-49
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• 1998

Microwave oven을 이용한 취반 시 최적 취반조건을 설정하기 위하여 전자렌지의 출력 및 가열시간을 달리하여 취반한 밥의 관능적 특성을 조사하였다. 쌀 1cup(약 173 g)을 수세하여 290 ml 물을 넣고 1시간동안 침지시킨 후 전자렌지의 출력과 가열시간을 5단계로 조절하면서 취반하였다(1단계; 온도상승기, 2단계: 수분흡수기1, 3단계: 수분흡수기2, 4단계: 열 침투기, 5단계: 호화완료기). 예비실험에서 설정한 출력과 가열시간에 따른 실험조건 수는 1200treatments였으나 1차, 2차에 걸친 취반실험 결과로부터 32가지의 최적 취반조건을 선정하였다. 그 중에서 다시 다음 3가지를 전자렌지의 대표적 인 취반조건으로 제시할 수 있었다. 1) 출력(7) 5:00-출력(1) 5:00(2) 5:00-출력(2) 6:00-출력(7) 4:00 2) 출력(8) 4:25-출력(1) 5:00-출력(2) 5:00-출력(2)

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2003년도 High Temperature Superconductivity Vol.XIII
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• pp.39-39
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• 2003